Wood filling material and method of its manufacture



Patented May 30, 1950 WOOD FILLINGMnTEnmmANn-METHon"-- or rrs MANUFAGTURE Drahomi'r Horsak, Brunn-Kralovo Poles;

Czechoslovakia 6 Claims" (01. 106-5196),

ThisinventionIelates .to. aiwood fillingsmaterial and. .to a methodeof,manufacturingi'iti The synthetic. mouldingumaterials, especially synthetic resins, .usually... have. 1a. ifiller of 1 wood? pulp; fibrous.1wood=cellu1ose.or. the. like, as. is LWEll known in the art..- Filledmassesiobtainedxm this way. have, however,a..low strsngth andj are .too fragile; .becauselthewfillingomaterials, inzl-consee quence of: .theinfine-graineducharacter; do; not provide. the r necessary. ,tou hnessa On the. 1con-. trar-y they .eventendto .reduceethei low cohesion of .the ,basic material...

The inventionrelatesioa woodfilling material for synthetic resinsof all. kindstzthe-materialicone sisting .ofibodiesc articulatedonlytto a relatively small degree and produceduwith theietention of the natural structure and'unimpaired cellular bond of 1. theawood .so that: ibyr'the strength and cohesion of its particles, whichiis'su-furtherina creased by impregnation, and. la feltingi-pr-ocess,-. it gives to the basic material considerable strength, elasticity and toughness. Products made of synthetlc materials filled in this way possess an in creased resistance not only to wear but also to impact.

The invention relates further to the use of wood filling material provided with a binder, hardenable or not, of the natural or synthetic I Theriillillgxsmaterial, being pliable doeswnot offer; any. resistance ,and canibeyeasily shaped into the 1 it is necessary tovtake care anzappropriate way;

resins type or other thermoplastic e. g. phenol formaldehyde or urea formaldehyde, synthetic resin, pitch, sulphur, asphalt, rosin, cellulose acetates or the like and treated according to known methods as plastics or powders for producing moulded or pressed articles of all kinds.

The new filling material consists essentially of wood bodies in the form of longitudinal leaves, strips or the like having substantial length and breadth but being very thin. The latter are obtained continuously and uniformly from preferably fresh or refreshed (e. g. steamed) wood by peeling, grating, or grinding, under the fullest possible retention of the natural structure and unimpaired cellular bond of the wood. The dimensions of the bodies are preferably between 0.02" to 0.002" thickness and many times this in length, their surface area being between 0.0016 to 16 sq. in. These particles are not brought into a more fibrous state. On the contrary, they must retain their characteristic formation and their rigid cellular bond in spite of being in a felted condition, when they are brought into contact with the basic material or the binding agent as well as during further treatment of the filled synthetic mass, when imparting shape e. g. by casting, spraying, pressing, moulding or the like.

most; complex formsie Experimentshave shown-thatsthe wood filling; materiahintheshapeqsuoh as rleaves, sheets,,strips,

chine; like may bereasilyrobtainediin considerable.

lengthiandr Widthi -and-; minimi1m.:thickness,; 1 thelmarmfactunewwoodzrisrused; which is as raw; as;.=possib1e and 1;; still; :contains...- its original hu: 1 miditiyfl or woodmpreliminam teamed. by Wet:

steam having a temperature between 1100fand 150?" centigrader If,'. according::to ,this. .method, .raw wood with. itsioriginali contents of :humidity has. to: be .used,

to;prev,ent.the raw woodfrom losing itshumidityr during, storage;.-;for:iinstance, by storing; it in wet: or by: permanently: spraying itgwith water.

Onrtheiiothemhandaaitzhas,;beenifoundparticuw larly advantageous to deprive the .woodeofaitsg humidity prior i;to.;.thecmanufacturer:(fominstance in special drying plants), if wood filling material has to be obtained having the shape of fibrous bodies such as fibres, needles, rods, longitudinal chips or the like.

The wood filling material according to this invention is produced by peeling, grating or grinding a rotating block of wood by means of a suitable tool, working as far as possible parallel to the axis of the block as well as to the direction of the natural fibres of the wood. The wood block should rotate at a speed of more than 300, and preferably more than 1000, revolutions per minute. A peeling tool works substantially in a. tangential direction, grating tools approximately in a radial direction and grinding tools again in a tangential direction. For the manufacture of longitudinal chips dry wood is well suited, whereas for obtaining two-dimensional bodies fresh or steamed wood is more preferable. A few practical examples will be given below.

A knife is automatically moved towards a rotating wooden block having a diameter of e. g. 8" and a length of 5 ft. The cutting edge of the knife, also 5 ft. long, is substantially parallel to the axis of the block. The feeding movement of the knife is perpendicular to the axis of the block, but the cutting edge is ground and positioned in such a way, that it engages the block in tangential direction. As soon as the knife engages the block it cuts along the circumference of the block a wooden leaf 5 ft. wide and say 0.008" thick, which can be of considerable length limited only by the diameter of the wooden block.

If the knife engages the block in such a way that its cutting edge is directed roughly towards the centre of the block, longitudinal fibres of a length of ft. and diameter of say 0.008" are formed at a suitable rotation of the block and speed of the feeding movement of the knife. As filling materials do not usually require such a length, dividing projections are provided on the knives, said projections being about 0.12" high and 0.04" wide and spaced from each other by about 8". If the knife engages the block tangentially long strips 8" wide and 0.008" thick are obtained. If the cutting edge of the knife is directed towards the centre of the block, chips 8 long and 0.008" thick are produced.

The wooden filling material according to the invention can be used in suitable relative quanti-; ties in connection with the widest varieties of.

synthetic masses, in particular with synthetic resins. For example, by mixing 60 parts of filling material in leaf form with 40 parts of aminoplast such as the urea formaldehyde aforementioned, a mass excellently suited for pressing or moulding is obtained, the mass being suitable in particular for the manufacture of articles subject to considerable loads such for example as handwheels for machine-tools. When coal pitch or asphalt is used as a binding agent a thermoplast mass is obtained which is suitable for spraying and can be used for the manufacture of insulating plates or other articles produced by spraying.

- I claim:

1. In a manufacture of the character described, wood in paper-thin pieces of about 16 square inches cut parallel to the grain and retaining the amount of water content natural to the wood, together with a binder uniting the pieces mostly in parallel planes but also heterogeneously.

2. A manufacture as claimed in claim 1 wherein the wood fragments are of 0.002 to 0.02 in. thickness.

3. A manufacture as claimed in claim 1 Q Number wherein the binder is about 40 per cent of the total.

DRAHOMiR HoRsAK.

REFERENCES CITED The following references are of record in the I file of this patent:

UNITED STATES PATENTS Name Date Re. 8,258 Meech May 28, 1878 106,710 Meech Aug. 23, 1870 228,899 Holmes June 15, 1880 1,446,888 Dyckerhoif Feb. 27, 1923 1,597,538 Novotny Aug. 24, 1926 1,633,738 Fish June 28, 1927 1,664,601 Ellis Apr. 3, 1928 1,832,807 Ellis Nov. 17, 1931 1,891,430 Loetscher Dec. 20, 1932 1,959,375 Loetscher May 22, 1934 2,066,734 Loetscher Jan. 5, 1937 2,095,652 Silberman Oct. 12, 1937 2,103,776 Geistlich Dec. 28, 1937 2,343,247 Simons Mar. 7, 1944 2,381,269 Elmendorf et al. Aug. 7, 1945 2,392,162 Lewis Jan. 1, 1946 OTHER, REFERENCES .Truax Forest Products Lab. Report 914, Oct. 1930. (4 pages.)

Koall Kustoife, vol. 34, pages 98-100; May 1944. 

1. IN A MANUFACTURE OF THE CHARACTER-DESCRIBED, WOOD IN PAPER-THIN PIECES OF ABOUT 16 SQUARE INCHES CUT PARALLEL TO THE GRAIN AND RETAINING THE AMOUNT OF WATER CONTENT NATURAL TO THE WOOD, TOGETHER WITH A BINDER UNITING THE PIECES MOSTLY IN PARALLEL PLANES BUT ALSO HETEROGENEOUSLY. 